Ableton Forum

Hello...

I've been running the dpc latency checker mentioned on other threads and realised that there are big 4000 micro-second spikes every 15secs. So I went through and checked through everything, as far as possible all non-music related drivers have been disabled. I finally got rid of the spikes only after removing the drivers for my edirol PCR50, the alesis multmix and the ATI display adaptor. After this the latency from the DPC was 10-20 micro-seconds.

On re-installation of my Alesis multimix16 usb2.0 driver, lo and behold, the latency spikes returned and the average latency went up to about 400-500 microseconds.

I was just wondering if anyone else has encountered such problems or has any advice?

Any help much appreciated.

muchos gracious

LT

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related threads/links:

windows optimisation by timur::

http://www.ableton.com/forum/viewtopic. ... highlight=

the latency checker::

www.thesycon.de/deu/latency_check.shtml

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7.0.3. Acer travelmate6460. 2xT7200@2Ghz. 2Gb RAM. XP-SP2.

Just realised that the alesis driver may not be the problem.

On using the sysinternals process monitor:

http://technet.microsoft.com/en-us/sysi ... 96645.aspx

I see that I am getting a load of 'NAME NOT FOUND' results when the RegOpenKey operation is called. See screen shot below, this seems to happen for a number of processes including some aluding to usbaudio. Does anyone know what any of this means???:?: ... I am about 100 miles out of my depth.

process mon screen



Cheerz.

LT [/img]

oh oh oh

almost forgot, here are some more related screen shots:

after alesis driver uninstall:



after alesis driver reinstall (jump at -25secs is where USB connection is made):



Yes I know everyone has seen these type of things a thousand times but what the heck!!!!

right I'm off to actually use live, glitches or nay. If anyone has any help I will be extremely thankful..

bye again.

LT

Did you check the IRQ list of your mainboard already? Most likely some other device shares a physical IRQ line with your USB controller (even if Windows shows something different). Try to find out about that.

Some guy on the RME forum had a similiar problem, he finally managed to solve it by disabling/enabling devices in BIOS which forced the mainboard to reorganize its IRQ scheme (eventhough Windows showed no problem with that before):

http://www.rme-audio.de/forum/viewtopic.php?id=2451

Is the Alesis driver needed to run the device or can you use standard Windows USB Audio Device drivers instead? And finally but most important, do you experience problems or are you just alarmed by the DPC reading?

Udo.Eberhardt@thesycon.de wrote:Note that dpclat does not perform an exact measurement of DPCs occurring in other drivers. It schedules a DPC every millisecond and performs a statistical analysis of the delay between the issuance and the time when the DPC runs. If there is any other DPC in the system that runs for a few more microseconds then this will have an impact on the DPC of dpclat.

PS: The screenshot of your Processmon cannot be read (too small).

Cheers Timur,

First off here's a bigger version of the processmon screenshot:



.

I've tried to assess the IRQ lines, it seems that there is some sharing but that nothing can be done about it as it is part of ACPI? Screenshot below.



.

Also I've tried enabling/disabling in BIOS and have left the printer/serial ports disabled as are unused. This does not appear to have had any effect.

.

Finally, yes I do get the occasional drop out, especially noticable when recording audio. Also I feel like i'm coming down with helpless puppy syndrome and would like to have a 100% reliable system (if such a thing exists).

Thanks again,

LT[/img]

Your USB controller shares an IRQ (16) with the onboard graphic-card, that should only affect USB 1.1 though, since the 2.0 part uses its own IRQ (23). Did you try using different USB ports already (there are three physical USB lines each for 2 USB ports, that's why there are 3 USB 1.1 IRQs). Also try disabling Windows 2D accelleration (Display settings, Troubleshooting).

happy days ---> in the end it was resolved by disabling/enabling the realtek onboard sound and restarting. I have no clue why this worked.

Also, after asking about a bit, it appears that the NAME NOT FOUND issue I was going on about is pretty normal, they still irritate me though.

Thanks again for your help.

LT


etc